The embodiments of the invention disclosed herein generally relate to a medical device and medical procedure using that device, and more particularly, to a joint fusion assembly for arthroplastic convergence of opposing ends of bones.
Joint disorders, such as arthritis in the joints of digits, can be extremely painful. A common procedure to alleviate pain in such patients is to fixate the joint for fusion by arthrodesis. There are a number of arthrodesis techniques that promote fusion of adjacent bones of a digit (e.g., finger or toe). Historically, these techniques utilize a bone screw that draws the adjacent bones together at a 180 degree, or straight, angle. The digit then fuses at the joint in a fully-extended orientation. This fully-extended orientation of the digit in conventional arthrodesis techniques weakens grip strength and is often not esthetically pleasing to the patient. For example, the grip strength of the hand increases when the fingers can oppose each other as the hand grasps an object. If a finger is extended, it cannot properly oppose the other fingers to grasp the object, stabilize the object in the hand, or exert force on the object. Moreover, the digits of a human hand rest in a flexed position; therefore, a digit that is fused in an extended position looks abnormal and is not esthetically pleasing. Similarly, straight toe joints are unnatural and do not grip or fit properly within normal shoes.
One complication arising from the arthrodesis surgery is misalignment, or crooked, fusion at the joint. This can arise from imperfect alignment of the bone ends during surgery, subsequent misalignments caused by lateral impact during the healing process, or in the case of arthrodesis utilizing an implanted bone screw having a flexible joint, lateral rotation about the joint during healing. All three situations result in a digit that may heal in a different than desired orientation.
Accordingly, it would be an advantage to provide a joint assembly that overcomes the disadvantages of previous technology.